Species in the Spotlight

Sacramento River Winter-Run Chinook

The Sacramento River winter-run evolutionarily significant unit (called an "ESU") of Chinook salmon is one of NOAA Fisheries’ Species in the Spotlight. This initiative is a concerted, agency-wide effort to spotlight and save the most highly at-risk marine species.

Species in the Spotlight logo.

Chinook salmon are an iconic part of California’s natural heritage that must be preserved in order to ensure the economic and recreational wellbeing of future generations. Millions of wild salmon once returned to spawn in the foothills and mountains of California’s Central Valley. Streams fed by rainfall, snowmelt, and cold water springs encircled the valley, fostering a diversity and abundance of Chinook salmon. The endangered Sacramento River winter-run Chinook salmon are particularly important among California’s salmon runs because they exhibit a life-history strategy found nowhere else on the West Coast. These Chinook salmon are unique in that they spawn during the summer months when air temperatures usually approach their warmest.

As a result, winter-run Chinook salmon require stream reaches with cold water sources that will protect their incubating eggs from the warm ambient conditions. Because of this need for cold water during the summer, winter-run Chinook salmon historically occurred only in rivers and creeks fed by cold water springs, such as the Little Sacramento, McCloud, and Pit rivers, and Battle Creek.

The construction of Shasta and Keswick dams eliminated access to the Little Sacramento, McCloud, and Pit rivers, effectively causing the extirpation of the winter-run Chinook salmon populations that spawned and reared there. The fish from these different populations were forced to mix and spawn as one population downstream of Keswick Dam on the Sacramento River. The construction and operation of hydropower facilities in Battle Creek made the creek inhospitable to winter-run Chinook salmon, and that population also was extirpated.

The one remaining winter-run Chinook salmon population has persisted in large part due to agency-managed cold water releases from Shasta Reservoir during the summer and artificial propagation from Livingston Stone National Fish Hatchery’s winter-run Chinook salmon conservation program. Thus, winter-run Chinook salmon are dependent on sufficient cold water storage in Shasta Reservoir, and it has long been recognized that a prolonged drought could have devastating impacts, possibly leading to the species’ extinction.


Currently, Shasta and Keswick dams block winter-run Chinook salmon from nearly all of their historical spawning habitat.  The spawning habitat that is accessible is subject to water temperatures that are too warm to support egg and fry survival, particularly during the current California drought, which is one of the most severe on record. In addition to lost and degraded spawning habitat, 98 percent of riparian and floodplain habitat along the Sacramento River is no longer available to support juvenile rearing. Other threats to winter-run Chinook salmon include water withdrawals, predation by non-native species, lack of quality rearing habitat in the  Sacramento-San Joaquin Delta, and commercial and recreational fisheries.

Species Recovery

In 2014, NOAA Fisheries adopted a plan to recover Sacramento River winter-run Chinook salmon, as well as Central Valley spring-run Chinook salmon, and Central Valley steelhead.

A recovery plan is one of the most important tools in the species recovery process. It provides a sound scientific foundation and guides decision-making for partners implementing the plan and its actions. This recovery plan sets goals and prioritizes actions for the Sacramento-San Joaquin Delta and its watersheds, laying out steps to achieve the species’ recovery. It provides a framework for targeting conservation efforts and modifying actions based on new science and changing circumstances.

Recovery plans provide guidance and are voluntary; they do not have the force of law. As such, the success of recovery efforts ultimately depends on partnerships and cooperation to ensure the right actions are implemented to advance long-term species’ recovery.

State and federal agencies, public organizations, non-profit groups and others in California’s Central Valley have formed strong partnerships to save Sacramento River winter-run Chinook salmon. Efforts to protect winter-run Chinook salmon include restoring habitat, utilizing conservation hatchery programs, closely monitoring the population, and carefully managing scarce cold water. Additional key actions needed to safe guard winter-run Chinook salmon from further declines include:

  • Improving management of Shasta Reservoir’s storage in order to provide cold water for spawning adults, eggs, and fry, stable summer flows to avoid de-watering redds, and winter/spring pulse flows to improve smolt survival through the delta.
  • Completing the Battle Creek Salmon and Steelhead Restoration Project and reintroducing winter-run Chinook salmon to the restored habitat.
  • Reintroducing winter-run Chinook salmon into the McCloud River.
  • Improving Yolo Bypass fish habitat and passage so juveniles can more frequently utilize the bypass for rearing and adults can freely pass from the bypass back to the Sacramento River.
  • Managing winter and early spring delta conditions for improved juvenile survival.
  • Conducting landscape-scale restoration throughout the delta to improve the ecosystem’s health and support native species.
  • Expanding the Livingston Stone National Fish Hatchery’s facilities to support both the captive broodstock and conservation hatchery programs; and
  • Evaluating alternative control rules used to limit incidental take of winter-run Chinook salmon in ocean fisheries.

As part of our strategy to prevent extinction, we are developing a 5-year plan of action for this species that builds on the recovery plan and details the focused efforts that are needed over the next 5 years. We will continue to engage vital partners in the public and private sectors in actions they can take to support this important effort.